I am working on the the irrigation system in my backyard and after finding the cause of a spot that has been flooding (bad seal from supply line to riser) I have a question about the best way to fix it. The supply line is just pvc pipe and there is a female t-joint where the riser screws into and then the sprinkler goes on top of the riser. Everything is threaded.

The seal isn't good enough to prevent water from leaking where the riser is screwed into the t-joint. What is the best way to seal this? I see there has been blue glue use around other spots in the yard, but I really don't want to use this just in case I need to get it off again. Will thread tape work on male PVC to female PVC connections? Is it going to be good enough to stop the tiny leak I have? Should I use the blue glue instead on the joint?

Thanks!

GT

majakdragon

07-09-2007 01:05 PM

If you glue it, you are correct, you will not be able to get the joint undone again. Have you checked the tee for cracks? Teflon tape will work for threaded fittings as will joint compound. Both are actually lubricants and not made to seal leaks, just to allow the joints to go all the way together. Pipe threads are tapered so when they go all the way up, they seal.

GT4NE1

07-09-2007 01:11 PM

Thanks for the quick reply. I've checked the tee. It is definitely where the riser screws into the tee, because I screwed a cap onto it for a few days and the leak stopped, but I just can't get the riser screwed on as tight as I got the cap on.

So, I'm wondering if thread tape will allow the threads to be thicker, so when I screw it on, it will fill in any gaps that the water is leaking through.

majakdragon

07-09-2007 01:43 PM

It may or may not work. If you are wanting to fill in any gaps, I would use something like RectorSeal #5 pipe compound.

steve771

07-10-2007 12:00 PM

Quote:

Originally Posted by majakdragon
(Post 52248)

Both are actually lubricants and not made to seal leaks, just to allow the joints to go all the way together. Pipe threads are tapered so when they go all the way up, they seal.

I thought I had read that such products might let you 'overtighten' the plastic, causing problems that way? I haven't had much luck with pipe threads going all the way 'up' to seal. Don't take that wrong, it's just been my experience and I'm trying to learn here.

Rectorseal sounds like an interesting product, but can you unscrew it in case of a problem, or is it more of a 'glue' in that regard? And if you can break/unscrew the seal/connection, does it work well with dis-similar materials, i.e., a plastic male thread to a brass female? Ok, another rectorseal question. I see on their website they have the #5 you mention, but they also have a 'T plus 2'. Both seem applicable to the same sort of connection, except one is soft setting, slow drying and one is non setting. Why would you want one over the other? (unless that's the answer to my 'unscrew' question?) It's a little confusing...

GT4NE1

07-10-2007 12:28 PM

Update

Just to give an update. I used teflon tape on both ends of the riser last night and that sealed up the leak at the riser and the tee joint, but now the top of my brand new fixed sprinkler head is leaking.

I ran the sprinklers for a couple of seconds last night, the head popped up and sprayed great, but after I shut it off the head when down and continued to leak water the entire night.

I'm about ready to just cap it off and not have a sprinkler head. That is the only sprinkler causing problems with at least 3 other heads on the same zone. I don't get what the problem is.

majakdragon

07-10-2007 12:48 PM

Steve771, you can unscrew any joints made with Rectorseal products. I don't like products that dry hard because they can also crack or fail later. I have not seen the T plus 2. I normally use teflon on PVC type joints and Rectorseal on applications such as gas lines.
GT 4NE1, Sorry you are having such problems. Not sure why the head would leak after the zone shuts down. Normally a solenoid valve shuts off the water supply.

steve771

07-10-2007 01:08 PM

Ok, thanks. I know it probably sounds stupid, but I've tried teflon tape alone on plastic with limited success (sometimes it works, sometimes it doesn't, and I swear I use the same technique). The best solution I've found so far is teflon tape, then a light coat of PVC compound (thanks again, Ron!). But the rectorseal sounds interesting, I might give that a shot on the next (inevitable) leak.

On another note, we have fairly high water pressure where I'm at. What is the recommended maximum?

majakdragon

07-10-2007 03:20 PM

Good water pressure is between 40 and 80 pounds. Anything over 80 is considered high.

MechanicalDVR

07-10-2007 11:22 PM

Stick with teflon tape on plastic to plastic dopes let you over tighten plastic all too often.